In recent years it has become common for consumers of television broadcasts to make use of video recording devices (commonly known as videocassette recorders or VCRs) to make recordings of television programmes for their own use. One of the most common uses of the domestic VCR is to record a television programme which is being broadcast at a time when it is inconvenient for the householder to watch television, or at a time when the householder is occupied watching another desired programme on a different channel. The programme is recorded without necessarily being viewed at the time of recording, being replayed for viewing at a more convenient time. This process is commonly called time-shifted viewing.
One limitation of the prior-art time-shifted viewing method is that many programmes are broadcast with interruptions, such as non-programmes material, which may detract from the viewer's enjoyment. Non-programme material includes commercial messages, half-time breaks at sporting fixtures, editorial commentary during movies, station identifications and other material not essential to the programme. Interruptions of this nature are one significant reason why alternative methods are often chosen for viewing movies in particular, such as rental of pre-recorded interruption-free movies, or subscription television services which provide interruption free movies for a fee.
These methods also suffer limitations. Rental movies incur the inconvenience of having to physically collect the tape from a video library and return it after viewing, are costly compared to recording off-air, and can only be viewed over the relatively short period of time for which the tape is rented. Subscription services are generally of the pay-per-view type, in which the viewer pays a fee for each movie viewed, or time-based subscription, where the user pays a periodical fee for access to the service for a prescribed time, during which it can be utilised as much as desired. Both these types of subscription service require a complex and expensive distribution infrastructure and are expensive to operate, resulting in high cost to the consumer. One major problem with subscription television services is piracy, that is, the utilisation of free-to-air or cable signals by people who are not subscribers. Piracy is a cause of considerable financial loss to service providers, and much effort has been devoted to securing subscription or pay-per-view services against such abuse. The primary scheme for preventing piracy is to encrypt broadcasts in such a way as to render the signals unwatchable except with the aid of decoders available only to legitimate viewers. It is now also commonplace for such decoders to be equipped with control means which enable the service provider to enable or disable decoding from a central office, providing means of ensuring that individual subscribers cannot continue to use their decoders unless they have paid for the service, for example by monthly subscription. A further well-known extension of the system is the pay-per-view arrangement, whereby the charge for the service is based on usage. One charging method for pay-per-view involves issuing each user a certain number of credits in the form of data stored in the decoder. A predetermined number of these credits are consumed each time the user selects a programme to be decoded, and when all credits are consumed, the decoder ceases to function and the user must purchase further credits. For convenience credits can be issued by transmitting appropriate data to the decoder over the air or cable.
One limitation of such subscription services is that the equipment required to deliver programmes, encrypt and decode the programme signals, and manage the charging system is complex and expensive.
A further limitation of subscription services is that because many viewers prefer to watch programmes including interruptions rather than pay for viewing in cash, the demand for subscription services is not universal and hence both commercial and commercial-free systems must co-exist, with associated duplication of expensive resources.
A further difficulty for service providers which arises from the use of VCRs for time-shifted viewing of commercial television broadcasts is that users often use the fast-forward facility of a VCR to skip quickly through commercial messages on replay. This process, called "zipping", is of great concern to advertisers, who are paying to have their commercials broadcast at a rate based on the number of viewers. Because it is impossible to know how many viewers are zipping commercials, advertisers are often incorrectly charged.
The presence of non-programme material is also a cause of annoyance to many television viewers watching the programme as it is broadcast. A number of schemes have been proposed for eliminating unwanted material, in particular commercials, from television programmes being recorded or viewed. One approach uses an indicating signal transmitted from the same source as the television programme. An example of this scheme is apparatus manufactured by Logica Communications and Electronic Systems, London, known as an Advertisement Display Control Unit (ADCU). This equipment is intended for use with cable television systems for the purpose of eliminating advertisements in certain countries, where they are not permitted. Advertisements are indicated by a prescribed signal inserted into one line of the vertical interval of the television signal. On detection of this signal at a cable head end, the ADCU interrupts distribution of the transmission to viewers' homes, and substitutes a page of teletext vision, until such time as the advertisement is finished as indicated by the appropriate signal. While this scheme is effective for the purpose of controlling commercials on a country-by-country basis, it is designed to allow control of commercial-deletion from the point of origin of the broadcast, and does not allow individual viewers to choose whether or not they receive the commercials. Although it would be possible to adapt the system for domestic use, it would not be successful because broadcasters would lose considerable advertising revenue since it can be expected that many viewers would disable advertisements even in countries where television advertising is permitted. Without the cooperation of the broadcasters, who are required to transmit the signal indicating the presence of advertisements, this system can not work. Another scheme for eliminating unwanted material, which does not suffer this particular limitation, is described by Von Kohorn in U.S. Pat. No. 4,520,404.
According to this method, a monitoring station is provided where a person watches programmes received off-air and activates a transmitter which sends command signals indicating the presence of non-programme material to viewers' homes at the appropriate moments. The command signals are received separately from the television programme being viewed or recorded and utilised by a controller adapted to black out television display or pause recording while unwanted material is being received. Although this scheme is effective in achieving the object of allowing viewers to edit out unwanted material from broadcasts, it suffers from a number of shortcomings. In particular, the system does not provide a method of charging users on a basis of usage, nor is it possible to ascertain how many viewers are editing out commercials, since so long as the viewer is equipped with the editing system, it can be used as much or as little as desired.
The present invention is directed towards providing new and useful alternatives to known television programme distribution, editing and viewing arrangements.
According to prior-art television distribution systems, programmes are either encrypted and broadcast without commercials, in which case viewers must pay to be able to receive and decode these programmes, or programmes are transmitted in a form anyone can receive and view without payment, in which case the programmes are generally interrupted by commercials. According to this invention, programmes are transmitted unencrypted and with commercials and a signal indicating the presence of non-programme material is also transmitted, viewers being provided with controllers which cause elimination of unwanted material from viewing or recording. In this respect, the system is similar to that of Von Kohorn's U.S. Pat. No. 4,520,404. However the present invention further provides a system for enabling the elimination of unwanted material only while pre-purchased credit remains. Alternatively, the indicating signal can be embedded in the broadcast signal, for example in the manner of the Logica ADCU. In this case also, the present invention provides for revenue-control.
The present invention, therefore provides a significant benefit over the prior art in that members of the viewing public can choose whether they wish to view programmes, for example movies, free of charge but with interruptions, or to view programmes free of interruptions, but to pay a charge. One significant functional difference between the well known pay-per-view system and that of this invention is that whereas in the case of pay-per-view the viewer pays to receive or record a particular programme, in the case of this invention the viewer pays in order not to see or record certain material. This is of benefit to the viewer, in that the additional service is offered but does not interfere with the provision of the conventional commercial service, as the broadcast need not be encrypted since it is intended that anyone be able to receive it without charge. The invention is advantageous also to the broadcaster, as it allows provision of an additional service, and source of additional revenue, not unlike pay-per-view service, at very little capital or running cost. The invention is also beneficial to the advertisers who purchase advertising time during broadcasts as it allows the audience not watching the commercials to be more accurately assessed, so that advertisers can have greater confidence that the audience for which they are paying is being delivered. The advertisers also benefit in that the invention makes it less attractive to manually zap recordings, that is, remove commercials by manually pausing the VCR when recording a programme, or fast-forwarding through commercials when replaying.